MAC. Ltd manufacturers sheet music stands in two separate departments, cutting and welding. The following data relate to the year just ended:

1. MAC. Ltd manufacturers sheet music stands in two separate departments, cutting and welding. The following data relate to the year just ended: Cutting Welding Total plant department department Budgeted manufacturing overhead $60 000 $140 000 $200 000 Actual manufacturing overhead 54 000 108 000 162 000 Budgeted machine hours 50 000 110 000 160 000 Actual machine hours 27 000 90 000 117 000 Budgeted direct labour hours 30 000 20 000 50 000 Actual direct labour hours 29 400 11 700 41 100 5.0 One of MAC's major products, the B Frame, has the following production requirements: Cutting Department Welding Department Total plant Machine hours 3.5 5.0 8.5 Direct labour hours 2.0 7.0 Required: Calculate the manufacturing overhead cost of the B Frame using: a) a predetermined plantwide rate based on direct labour hours b) a predetermined plantwide rate based on machine hours c) predetermined departmental rates based on direct labour hours for the cutting department and on machine hours for the welding department. Which of these three estimates of overhead cost is likely to be the most accurate? Explain